package com.fan.sgginterview;

import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

/**
 * @author :  PF_23
 * @Description : 传统生产者-消费者
 * @date : 2020/04/10.
 */
class ShareData {  //资源类
    private int number = 0;
    private Lock lock = new ReentrantLock();
    private Condition condition = lock.newCondition();

    public void increment() throws Exception {
        lock.lock();
        try {
            //1.判断
            while (number != 0) {
                // 等待，不能生产
                condition.await();
            }
            // 干活
            number++;
            System.out.println(Thread.currentThread().getName() + "\t" + number);
            //3.通知唤醒
            condition.signalAll();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            lock.unlock();
        }
    }

    public void decrement() throws Exception {
        lock.lock();
        try {
            //        1.判断
            while (number == 0) {
//            等待，不能生产
                condition.await();
            }
            //2.干活
            number--;
            System.out.println(Thread.currentThread().getName() + "\t" + number);
            //3.通知唤醒
            condition.signalAll();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            lock.unlock();
        }

    }

}

/**
 * 题目：一个初始值为0的变量，两个线程对其交替操作，一个加1，一个减1，来5轮
 * <p>
 * 1.线程 操作 资源类
 * 2.判断 干活 通知
 * 3.防止虚假唤醒机制
 */
public class ProdConsumer_TraditionDemo {
    public static void main(String[] args) {
        ShareData shareData = new ShareData();
        new Thread(() -> {
            for (int i = 1; i <= 5; i++) {
                try {
                    shareData.increment();
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }, "AAA").start();

        new Thread(() -> {
            for (int i = 1; i <= 5; i++) {
                try {
                    shareData.decrement();
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }, "BBB").start();
    }
}

